Flexible LED strips as grow lights?

[Doofinator]

Thanks guys. I'll see which one I'd mine sacrificing the least, and that'll be the experimental one.

Have a good one.

[Robe]

Hello anyone!
I'd like to contribute to this thread since I started playing with LED strips few months ago. Thanks for all the info
I acknowledge that professional LED systems are surely superior than any DIY solution based on these strips but... well, I decided to go the cheap way... for now.

My orchidarium is 80cm x 40cm x h50cm. I opted for a fixed light setup since the orchidarium isn't that high but mainly for aesthetic reasons. I glued the strips to some aluminium bars (like this), very cheap and I think they could help dissipating some heat from the LEDs

Now, AT LAST, let's talk about the lights.
I decided to get the 5730 Epistar version from Aliexpress: cheap as heck and, according to them, very efficient.
HERE I found a datasheet of the 5730. I attached the spectra of the warm/natural/cool white version so you can compare it with the chlorophyll one.

I bought the cool white and the warm white, both in the waterproof version. I know some of you prefer to get the 4000K light only, I chose to have a higher blue peak and try to reach the far red. Well, the limits of these lights are so visible now if compared to professional LEDs' spectra
I placed 210cm of cold white strip and 140cm of warm white (about 40W) but I am considering placing 70cm more of each.

Let's talk about the light intensity, as you said it's quite difficult to know the lumens these little things emit.
You said 40/50 lumens... well I also got that value but it's PER LED! Umph...

How accurate is this datasheet for the final performance of the strip, in your opinion?
Let's consider in the datasheet the 5730's power is 0.5W, this would make 30W for one meter of the strip, 3 times the actual power. Damn this is so confusing.

We all love photos, I know

[naoki]

Looking nice, Robe! The enclosure looks like a nice one, too. You need more plants! Or did the Stegosarus eat them?

Originally Posted by Robe

I acknowledge that professional LED systems are surely superior than any DIY solution based on these strips but...

I'm not sure about that, at this time, you can get higher efficiency LEDs with DIY than pre-made fixtures at a fraction of the cost.

Originally Posted by Robe

Let's talk about the light intensity, as you said it's quite difficult to know the lumens these little things emit.
You said 40/50 lumens... well I also got that value but it's PER LED! Umph...

How accurate is this datasheet for the final performance of the strip, in your opinion?
Let's consider in the datasheet the 5730's power is 0.5W, this would make 30W for one meter of the strip, 3 times the actual power. Damn this is so confusing.

The datasheet is a bit confusing, but it appears that the data is based on 6x 5730 connected serially (the bottom PDF which says "6 chips series"). While I'm not completely familiar with this type, 5730 is supposed to be the copy of Samsung 5630, and comparing the data sheet of 5630 with 5730 seems to indicate that the data sheet is giving the spec for 6 diodes. If this is the case, forward voltage per diode is about 3V. 5730 by itself seems to have decent efficiency (around 108lm/W). But there are resistors embedded in the strip, so the actual efficiency is lower (maybe 3/4 of 108 lm/W)?

I think that you are coming up with 0.5W number from 18.5V * 0.03A in the data sheet. But if the strip is using lower current, it won't be running at 0.5W. Since it uses 12V constant voltage driver, the actual current is determined by the resistors embedded in the strip.

If you can measure the voltage across each diode, and amount of current (ampage) with a multimeter, you can get the approx lumen output from the data sheet.

I'm curious to see the measurement, but if your plants are growing well, it is probably good enough, don't you think?

[Robe]

Hello naoki! Thanks so much for your reply, I've carefully read and ejoyed your threads about DIY LEDs and PAR things. The other contributors and you have answered so many questions in those threads, thank you.

Originally Posted by naoki

Looking nice, Robe! The enclosure looks like a nice one, too. You need more plants! Or did the Stegosarus eat them?

LOL I do need more plants, the whole orchidarium is only few weeks old aaand there's still so much place to fill (but I know it'll end too soon).
I tried to train the little dinos to hunt the evil snails or other pest, if any will appear (hope not), I'll let you know if the training was successful

Originally Posted by naoki

[...] at this time, you can get higher efficiency LEDs with DIY than pre-made fixtures at a fraction of the cost.

Well, sure if you're an electronics nerd like us, I guess that's a step beyond the simple LED strip tho.
I will follow you in playing with those very soon I hope

Originally Posted by naoki

The datasheet is a bit confusing, but it appears that the data is based on 6x 5730 connected serially (the bottom PDF which says "6 chips series").

I had read that "6 chips series" but I hadn't been able to figure out what its meaning was. Is my strip a 6 chip type or 5? How can we tell? I can see 3 LEDs per portion and I guess they're connected parallelly together with 2 resistors.

Originally Posted by naoki

I'm curious to see the measurement, but if your plants are growing well, it is probably good enough, don't you think?

Thanks so much!
Damn I am almost blind but I got the measurements
You were right, we have 3V for each diode and 120mA, so about 0.35W. The resistor here is 24ohm I guess.
How can you estimate the lumens from these data?

[naoki]

Thanks for the measurement, Robe. I haven't played with this kind of LEDs, but my understanding is that this kind of strip is wired in this way (please correct me if I'm wrong):

|--  >|  --  >|  -- >| -- VVV --|
|                               |
|--  >|  --  >|  -- >| -- VVV --|
|                               |
|--  >|  --  >|  -- >| -- VVV --|
|                               |
  +         12V driver        -

">|" is the LED
"VVV" is the adjusting resistor, so that 12V constant voltage driver can be used to give the proper forward voltage for the diodes.

Yours appear to have 3 diodes as a unit (of serially connected), so it requires around 3V * 3 = 9V. But you are using 12V constant current power supply, so the resistors are adjusting and wasting the extra energy.

120mA is a bit more than the maximum which 5730 can take. When you measured the ampage, I think that you probably took the measurement from several parallel circuit. In other words, if you had 12 LEDs, then it has 3 serially connected diodes in 4 parallel circuit. If you get 120mA from this, then each serially connected unit is getting 120/4=30mA (which is the approximate amount of forward current at 3V of forward voltage from the data sheet).

The data sheet says at 30mA, 60/6=10lumen per diode is the output. But the specification is at 25C temperature, and the output decreases with the temperature (see Relative Flux vs Ambient Temperature figure). So without the temperature, we don't know exact output (maybe 80-95%?). If you have total of 3.5m (210 diodes = 60 pcs/m * 3.5m), you get the total output of 2100 lumen (or less, depending on the heat).

If you have something like Kill A Watt, you can measure how much energy is consumed including the driver. The driver efficiency has a big effect in overall efficiency.

[Robe]

Hey, thanks for your reply and sorry for being late.
I can't see any internal wiring but my google research confirms that your diagram should be correct for most of the strips, hence so are your estimates. My strip has 2 resistors and 3 LEDs in each segment though, so probably the internal wiring is different. I'll try to destroy one segment to see how it is wired inside

I also thought of measuring from a node with many leds in parallel, I took it exactly at the border of a single LED. I hope that finding the internal scheme will solve this.

I will of course try to measure the total power that is consumed, my power meter is arriving from China
I will let you know how much power I consume (maybe after I'll add the more 1.4m of strips) and the total estimate for the lumens
thanks a lot!

[isa86]

i have seen this type of strips (but with red/blue leds) for sale at websites like aliexpress... i've thought of ordering some as an inexpensive solution for some of my shelves, since i don't think natural light is enough there.
i'm not sure if these are any good, they are so cheap, and i have no idea how grow lights are supposed to work.